Originally Posted by RobF
Diffraction doesn't do anything to the lens. It's a propery of it. It's just light passing through it in a scattered manner, and at the wavelength end of things it's allowing the light waves to seperate based upon their wavelength. It still doesn't alter the lens's physical character, it's still the same size, shape and density, which is what controls how light behaves through a lens.
Unlike heat which does change it's size, shape, and density and thus alters how light passes through it. But more likely the expansion of items in the scope's construction just moves the parallax lens assembly a fraction of a mm and it focuses to a slightly different point.
OK I'll bite.
The question was does light effect it, I'm saying yes it does because there's a soft machine and another lens behind it. I'm not saying the lens changes. Diffraction changes the quality of the image, targets in dark often appear softer and targets on the horizon with the sun low will white out. Are they not examples of light effecting it?
You're a camera guy, you must have stopped down a lens to get a better image surely?